who is eating my RAM.. :X

i'm using Go Launcher Ex, and can see my available RAM over the total 418MB..
when i boot my phone i have around 250MB (using only basic services, FB, Gmail, Minimalistic text)
NO WIDGETS..!!
after i run a few apps it keeps going down..
even though i end them and then force close them in settings..
still the RAM keeps decreasing.. it reaches upto 90MB free over 418MB.. :/